The stars of YouTube didn't choose to be famous - they happen to be captured on tape doing stupid things, and thanks to the Internet, gained unwanted infamy.
Here's an interesting article by John Cook for Radar Online, about the Prisoners of YouTube:
According to research by the Viral Factory, a marketing firm that specializes in viral videos, four of the top 10 most-watched online videos ever feature private or semi-private moments that were, like Aminrazavi's performance at the beach, never intended for a wide audience. Their protagonists are, by and large, regular people who woke up one morning to find that their lowest moments had been caught on camera and distributed to the snickering online hordes.
If you're not careful, you could be next.